1. Field of the Invention
This invention relates to information retrieving service systems, and particular to an information retrieving information retrieving service system using communication.
2. Related Art
Recently, information service systems utilizing communication functions are known. For example, when a user operates a user terminal to establish a data communication enabled state between the terminal and a center and to request retrieval of predetermined information, an information database at the center is searched and information corresponding to the request for retrieval is distributed.
However, such conventional information service systems have had the following problems.
(1) In order to retrieve desired information, a user terminal may request a center to retrieve the information using, for example, keywords as conditions for retrieval. It has been difficult to set such conditions for retrieval because a great number of keywords must be input to retrieve desired information exactly.
(2) An enormous amount of time and labor needed to construct an information database at a center results in relatively high information charges.
(3) The difficulty of real-time updating of an information database at a center increases with the ratio of the amount of rapidly changing dynamic information present in the database.